System and method for modular storage of measurement streams using a hierarchy of stream-processing objects

ABSTRACT

A method and system for modular storage of measurement streams using a hierarchy of stream-processing objects. A first application may log measurement data of a plurality of data types to a shared memory location on a first computer, independent of the data type. Both the data and an index to the data may be logged. A second application may trend the data substantially concurrently as the data is logged. Both applications may include a plurality of filter objects, including a hierarchy of stream processing objects, which may operate to log/trend the data. Trending may include: (1) generating a query; (2) determining the location using the index; (3) accessing the data from the shared memory; and (4) displaying the data. The data may be replicated to an archival database, independent of the type of data. The replicated data may be transmitted to a plurality of computers.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to computer software, and moreparticularly to storage and retrieval of multiple types of measurementstreams.

[0003] 2. Description of the Related Art

[0004] Various measurement devices may provide different measurementstreams (e.g., value-time pairs, data acquisition (DAQ) data).Typically, separate software application programs are required toprocess different types of measurement data (e.g., different measurementstreams). Conventional database configuration typically implies thatcertain characteristics (e.g., persistence (storage on disk), caching,replication, networking, security) are dependent upon the type of datastored in the database. It is desirable to have robust softwareapplication programs that are able to process multiple types ofmeasurement data using a shared code base. Benefits of a shared codebase may include a smaller footprint (i.e., code size) and ease ofmaintenance.

[0005] For the foregoing reasons, there is a need for a system andmethod for modular storage of multiple types of measurement streams(i.e., input data).

SUMMARY OF THE INVENTION

[0006] The present invention provides various embodiments of a system,method, and medium for modular storage of measurement streams using ahierarchy of stream-processing objects.

[0007] A first application may log or write first measurement data to ashared memory location on a first computer system. The first measurementdata may include one or more types of measurement data (e.g., live dataacquired from a data acquisition device; waveform data; single-pointdata, wherein single-point data comprises a data value and a datatimestamp; alarm data; event data, among others). The first applicationprogram may receive measurement data of a plurality of data types from aplurality of measurement devices prior to logging or writing or storingthe first measurement data. The storing of the first measurement datamay be independent of the data type of the measurement data.

[0008] The first application may include a plurality of first filterobjects which operate to log the first measurement data. The pluralityof first filter objects may include a hierarchy of first streamprocessing objects.

[0009] Logging may include receiving the first measurement data from afirst measurement device, and storing the first measurement data in theshared memory location. Typically, the shared memory location is storedin a volatile memory. Storing the first measurement data may includestoring the first measurement data in the shared memory location andstoring an index to the first measurement data, wherein the index isalso stored in the shared memory location.

[0010] A second application may trend, read, or retrieve the firstmeasurement data, or at least a subset of the first measurement data,from the shared memory location on the first computer systemsubstantially concurrently as the first measurement data is logged tothe shared memory location on the first computer system by the firstapplication.

[0011] Similar to the first application, the second application mayinclude a plurality of second filter objects which operate to trend thefirst measurement data. The plurality of second filter objects mayinclude a hierarchy of second stream processing objects. The pluralityof first filter objects and the plurality of second filter objects mayshare filter objects.

[0012] Trending may include: (1) generating a query for the firstmeasurement data stored in the shared memory location; (2) determiningthe location of the first measurement data in the shared memory usingthe index of the first measurement data; (3) accessing the firstmeasurement data from the shared memory; and (4) displaying the firstmeasurement data on a display.

[0013] The first measurement data stored in the shared memory locationof the first computer system may be replicated to an archival database.The replication of the first measurement data may be independent of thetype of measurement data. Thus, the replication may not require aversion of the application software able to read and/or write any typeof measurement data (i.e., the first application or the secondapplication). When updated software to support a new data type for atleast one of the first application and the second application isinstalled on the first computer system, the replication of the firstmeasurement data may support the new data type without modification.

[0014] The archival database may be stored on the first computer system.Alternatively, the archival database may be stored on a second computersystem, the second computer system being coupled to the first computersystem via a network.

[0015] The second computer system may transmit the replicated data to aplurality of computer systems. Similarly, in the case where the archivaldatabase is stored on the first computer system, the first computersystem may transmit the replicated data to a plurality of computersystems.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A better understanding of the present invention can be obtainedwhen the following detailed description of several embodiments isconsidered in conjunction with the following drawings, in which:

[0017]FIG. 1 illustrates a computer system connected through a networkto a second computer system;

[0018]FIGS. 2A and 2B illustrate representative instrumentation andindustrial automation systems including various I/O interface options;

[0019]FIG. 3 is a block diagram illustrating an overall architecture ofa shared memory architecture for high speed logging and trending,according to one embodiment;

[0020]FIG. 4 is a screen shot of high speed trending, according to oneembodiment; and

[0021]FIG. 5 is a flowchart illustrating a system and method for modularstorage of measurement streams using a hierarchy of stream-processingobjects, according to one embodiment.

[0022] While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the present invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS

[0023]FIG. 1: Computer System Connected to a Network

[0024]FIG. 1 illustrates an exemplary computer network in which acomputer system 82 is connected through a network 84 to a secondcomputer system 86. The computer system 82 and the second computersystem 86 can be any of various types, as desired. The network 84 canalso be any of various types, including a LAN (local area network), aWAN (wide area network), or the Internet, among others.

[0025] The computer system 82 includes or stores a first client computerprogram operable to store multiple types of measurement streams and asecond client computer program operable to retrieve multiple types ofmeasurement streams. In one embodiment, the data in the measurementstreams may be of various types, as described below. The data may residein a database on the computer system 82 or on the second computer system86.

[0026] The first client computer program and the second client computerprogram may be implemented in any of various ways, includingprocedure-based techniques, component-based techniques, and/orobject-oriented techniques, among others. The programs may be writtenusing any combination of text-based or graphical programming languages.Also, the programs may be written using distributed modules orcomponents so that so that the first client computer program, the secondclient computer program, and the database may reside on any combinationof computer system 82, computer system 86, and other computer systemsconnected to the network 84.

[0027] FIGS. 2A and 2B: Instrumentation and Industrial AutomationSystems

[0028]FIGS. 2A and 2B illustrate exemplary systems which may store oruse the first client computer program and the second client computerprogram. These programs may of course be stored in or used by othertypes of systems as desired.

[0029]FIG. 2A illustrates an instrumentation control system 100. Thesystem 100 comprises a host computer 102 which connects to one or moreinstruments. The host computer 102 comprises a CPU, a display screen,memory, and one or more input devices such as a mouse or keyboard asshown. The computer 102 may connect through the one or more instrumentsto analyze, measure, or control a unit under test (UUT) or process 150.The host computer 102 may store the first client computer program andthe second client computer program. The data stored by the first clientcomputer program and retrieved by the second client computer program maybe acquired from the one or more instruments. In other words, thecomputer 102 may be either of computers 82 or 86.

[0030] The one or more instruments may include a GPIB instrument 112 andassociated GPIB interface card 122, a data acquisition (DAQ) board 114and associated signal conditioning circuitry 124, a VXI/VME chassis orinstrument 116, a PXI chassis or instrument 118, a video device 132 andassociated image acquisition card 134, a motion control device 136 andassociated motion control interface card 138, and/or one or morecomputer based instrument cards 142, among other types of devices.

[0031] The GPIB instrument 112 is coupled to the computer 102 via theGPIB interface card 122 provided by the computer 102. In a similarmanner, the video device 132 is coupled to the computer 102 via theimage acquisition card 134, and the motion control device 136 is coupledto the computer 102 through the motion control interface card 138. Thedata acquisition board 114 is coupled to the computer 102, and mayinterface through signal conditioning circuitry 124 to the UUT. Thesignal conditioning circuitry 124 preferably comprises a SCXI (SignalConditioning eXtensions for Instrumentation) chassis comprising one ormore SCXI modules 126.

[0032] The GPIB interface card 122, the image acquisition card 134, themotion control interface card 138, and the DAQ card 114 are typicallyplugged in to an I/O slot in the computer 102, such as a PCI bus slot, aPC Card slot, or an ISA, EISA or MicroChannel bus slot provided by thecomputer 102. However, these cards 122, 134, 138 and 114 are shownexternal to computer 102 for illustrative purposes.

[0033] The VXI/VME chassis or instrument 116 is coupled to the computer102 via a VXI bus, MXI bus, or other serial or parallel bus provided bythe computer 102. The computer 102 preferably includes VXI interfacelogic, such as a VXI, MXI or GPIB interface card (not shown), whichinterfaces to the VXI chassis 116. The PXI chassis or instrument 118 ispreferably coupled to the computer 102 through the computer's PCI bus.

[0034] A serial instrument (not shown) may also be coupled to thecomputer 102 through a serial port, such as an RS-232 port, USB(Universal Serial bus) or IEEE 1394 or 1394.2 bus, provided by thecomputer 102. In typical instrumentation control systems an instrumentwill not be present of each interface type, and in fact many systems mayonly have one or more instruments of a single interface type, such asonly GPIB instruments.

[0035] The instruments are coupled to the unit under test (UUT) orprocess 150, or are coupled to receive field signals, typicallygenerated by transducers. The system 100 may be used in a dataacquisition and control application, in a test and measurementapplication, a process control application, or a man-machine interfaceapplication.

[0036]FIG. 2B illustrates an exemplary industrial automation system 160.The industrial automation system 160 is similar to the instrumentationor test and measurement system 100 shown in FIG. 2A. Elements which aresimilar or identical to elements in FIG. 2A have the same referencenumerals for convenience. The system 160 may comprise a computer 102which connects to one or more devices or instruments. The computer 102comprises a CPU, a display screen, memory, and one or more input devicessuch as a mouse or keyboard as shown. The computer 102 connects throughthe one or more devices to a process or device 150 to perform anautomation function, such as MMI (Man Machine Interface), SCADA(Supervisory Control and Data Acquisition), portable or distributed dataacquisition, process control, advanced analysis, or other control. InFIG. 2B, the computer 102 may store the first client computer programand the second client computer program. The data stored by the firstclient computer program and retrieved by the second client computerprogram may be acquired from the automation system 160. In other words,the computer 102 may be either of computers 82 or 86.

[0037] The one or more devices may include a data acquisition (DAQ)board 114 and associated signal conditioning circuitry 124, a PXIchassis or instrument 118, a video device 132 and associated imageacquisition card 134, a motion control device 136 and associated motioncontrol interface card 138, a fieldbus device 170 and associatedfieldbus interface card 172, a PLC (Programmable Logic Controller) 176,a serial instrument 182 and associated serial interface card 184, or adistributed data acquisition system, such as the Fieldpoint system 186available from National Instruments, among other types of devices.

[0038] The DAQ card 114, the PXI chassis 118, and the image acquisitioncard 134 are preferably connected to the computer 102 as describedabove. The serial instrument 182 is coupled to the computer 102 througha serial interface card 184, or through a serial port, such as an RS-232port, provided by the computer 102. The PLC 176 couples to the computer102 through a serial port, Ethernet port, or a proprietary interface.The fieldbus interface card 172 is preferably comprised in the computer102 and interfaces through a fieldbus network to one or more fieldbusdevices. Each of the DAQ card 114, the serial card 184, the fieldbuscard 172, the image acquisition card 134, and the motion control card138 are typically plugged in to an I/O slot in the computer 102 asdescribed above. However, these cards 114, 184, 172, 134, and 138 areshown external to computer 102 for illustrative purposes. In typicalindustrial automation systems a device will not be present of eachinterface type, and in fact many systems may only have one or moredevices of a single interface type, such as only PLCs. The devices arecoupled to the device or process 150.

[0039] Referring again to FIGS. 2A and 2B, the computer system 102preferably includes a memory medium on which one or more computerprograms or software components according to the present invention arestored. The term “memory medium” is intended to include an installationmedium, e.g., a CD-ROM, floppy disks 104, or tape device; a computersystem memory or random access memory such as DRAM, SRAM, EDO RAM,Rambus RAM, etc.; or a non-volatile memory such as a magnetic media,e.g., a hard drive, or optical storage. The memory medium may compriseother types of memory as well, or combinations thereof.

[0040] In addition, the memory medium may be located in a first computerin which the programs are executed, or may be located in a seconddifferent computer which connects to the first computer over a network,such as the Internet. In the latter instance, the second computerprovides the program instructions to the first computer for execution.Also, the computer system 102 may take various forms, including apersonal computer system, mainframe computer system, workstation,network appliance, Internet appliance, personal digital assistant (PDA),television system or other device. In general, the term “computersystem” can be broadly defined to encompass any device having at leastone processor which executes instructions from a memory medium.

[0041] In one embodiment, the first client computer program and thesecond client computer program are designed for dataacquisition/generation, analysis and/or display. For example, in oneembodiment, the first client computer program is the NationalInstruments LabVIEW graphical programming environment application, whichprovides specialized support for developers of instrumentation andindustrial automation applications. An example of the second clientcomputer program is the Historical Viewer in Measurement & AutomationExplorer (MAX), a National Instruments product.

[0042] However, it is noted that the present invention can be used for aplethora of applications and is not limited to instrumentation orindustrial automation applications. In other words, FIGS. 2A and 2B areexemplary only, and data acquisition and/or data retrieval programs forany of various types of purposes may be used, where the programs arestored in and execute on any of various types of systems.

[0043]FIG. 3: Overall Architecture

[0044]FIG. 3 illustrates one embodiment of a block diagram illustratingan overall architecture of a shared memory architecture for high speedlogging and trending.

[0045] As used herein, logging refers to writing data and trendingrefers to reading and displaying data. As used herein, “alarm and event(A & E) data” are types of data that a subsystem, e.g., an alarmsubsystem, stores (e.g., events, alarm-set events, alarm-reset events,alarm acknowledgement events).

[0046] As used herein, “alarm data” may be a stream of occurrences whereeach occurrence may be one of three types: set, clear, or acknowledge.Set occurrences may include: a name, a timestamp, a priority, a user(i.e., name of the person logged in when the alarm occurred), an area(i.e., name that may be used to organize alarms into groups), and adescription. Clear occurrences may include: a name, a timestamp, and auser (i.e., name of the person who was logged in when the alarmcleared). Acknowledge occurrences may include: a name, a timestamp, auser (i.e., name of the person acknowledging the alarm), and a comment(e.g., a string describing why the alarm occurred and how it was dealtwith). As used herein, “event data” may be a stream of event occurrenceswhere each event occurrence may include: a name, a timestamp, a user(i.e., name of the person logged in when the event occurred), and adescription.

[0047] As used herein, “attribute data” may include a set of attributesor name-value pairs associated with each trace in a streaming database(SDB). As used herein, “process data” is a type of data for which valueschange slowly. When a value change that is more than a user-specifiedthreshold is detected, the changed value and a timestamp are logged. Asused herein, “single-point data” is a type of data that is acquiredasynchronously from one or more input channels and logged as a stream ofvalue-timestamp pairs. As used herein, “waveform data” is acquiredsynchronously and stored using an initial timestamp and which mayinclude a time interval representing the time between successive points.

[0048] As used herein, an “observer” is a component that keeps streamingdatabases (SDBs) on different computers synchronized with each other. Asused herein, a “reader” is a software program or object, e.g., a filterobject, for reading data of various types. As used herein, a “writer” isa software program or object, e.g., a filter object, for writing data ofvarious types. As used herein, a “streaming database” (SDB) is acomponent that stores sub-traces or streams of data, or arrays of bytes,into sequences of a certain page size, such as 4 KB pages, in a sharedmemory or on a disk. The pages of changes may be referred to as deltapages. As used herein, a “delta page” is a structure that represents thedifference between the current state of a page in a client's cache andthe current state of the page in the server's database.

[0049] As shown in FIG. 3, single-point writers 302 and 303 may be usedto log value-timestamp pairs. Similarly, single-point readers 302 and303 may be used to display previously logged data.

[0050] Alarm and event (A&E) writers 304 and 305 may be used to logevents (e.g., alarm set events, reset events, acknowledge events). A&Ereaders 304 and 305 may be used to determine when an alarm has beenacknowledged. A&E readers 304 and 305 may also be used to read events,to be stored in a database (e.g., a relational database).

[0051] Waveform writers 306 and 307 may be used to write high-speed data(e.g., up to millions of samples per second, or at a rate of up to 250kHz). Waveform readers 306 and 307 may be used to retrieve and displaydata.

[0052] As used herein, a “shared memory template” is a data structure,such as a C++ construct. A “shared memory template” may be functionallysimilar to the map template in the C++ standard template library. Sharedmemory templates may store data such that the data may be safely sharedamong multiple processes. A browser 301 may expose shared memorytemplates for users to enable browsing of data in both a local SDB 309and remote SDBs (e.g., SDB 308). A user may build upon the shared memorytemplates exposed by the browser 301 to allow multiple types of data tobe browsed. The shared memory templates may allow the type of data tobrowse to be user configurable.

[0053] A streaming database (SDB) 308 or 309 may be a shared-memorydatabase including sub-traces (e.g., collections of 4 KB pages or deltapages) and associated attributes of the sub-traces. From an SDB'sperspective, the previously mentioned writers and readers (e.g., 302through 307) deal with delta pages.

[0054] Observers 314 or 315 may be responsible for remote browsing,replication, configuration and/or subscribing, and networking. Anobserver, may read a delta page and modified attributes from a sourceSDB, and may subsequently send the delta page to a client observer. Forexample, observer 314 may read a delta page 310 and modified attributesfrom a source SDB 308 and may subsequently send or replicate 318 thedelta page to a client observer 315. Similarly, observer 315 may read adelta page 311 and modified attributes from a source SDB 309 and maysubsequently configure or subscribe 317 the delta page to a clientobserver 314. The client observer may write delta pages and modifiedattributes to a local SDB. Thus, observer 314 may write delta pages 312to SDB 308 and observer 315 may write delta pages 313 to SDB 309.

[0055]FIG. 4: Screen Shot of High Speed Trending

[0056] One embodiment of a trender application program (i.e., theHistorical Viewer in Measurement & Automation Explorer (MAX), a NationalInstruments product) is shown in FIG. 4. The MAX program may beconfigured to repeatedly read data from a stored location (e.g., ashared memory location) and subsequently display the data on a displaydevice. Later data may be continuously logged to the storage location atthe same time that earlier data is displayed to the user.

[0057] As shown in FIG. 4, a logging task is displayed. Acquisition ofdata may be user configured to start in response to an analog trigger ora digital trigger. Additional user configurable options may include: (1)start and stop data acquisition at user specified times; (2) publishacquired data to a data socket; (3) define and log virtual channels; (4)define and log calculated channels; (4) define and log events (e.g.,high, low, outside range, inside range); (5) display data (e.g., in realtime or historical data) in a HyperTrend, among others. In oneembodiment, the HyperTrend is a user-interface component developed byNational Instruments and available with its LabVIEW DSC, Lookout, and VILogger products. The HyperTrend may support the viewing of both currentand historical data retrieved from a database. The HyperTrend may allowthe user to perform multiple tasks, such as browsing for data,displaying data in a chart, and submitting queries for breaks, minima,and maxima in a stream of data that has been logged to a database, amongothers.

[0058]FIG. 5: Modular Storage of Measurement Streams

[0059]FIG. 5 is a flowchart illustrating a system and method for modularstorage of measurement streams using a hierarchy of stream-processingobjects, according to one embodiment.

[0060] In step 502, a first application may log or write firstmeasurement data to a shared memory location on a first computer system.The first measurement data may include one or more types of measurementdata (e.g., live data acquired from a data acquisition device; waveformdata; single-point data, wherein single-point data comprises a datavalue and a data timestamp; alarm data; event data, among others). Thefirst application program may receive measurement data of a plurality ofdata types from a plurality of measurement devices prior to logging orwriting or storing the first measurement data. The storing of the firstmeasurement data may be independent of the data type of the measurementdata.

[0061] The first application may include a plurality of first filterobjects which operate to log the first measurement data. The pluralityof first filter objects may include a hierarchy of first streamprocessing objects.

[0062] Logging may include receiving the first measurement data from afirst measurement device, and storing the first measurement data in theshared memory location. Typically, the shared memory location is storedin a volatile memory. Storing the first measurement data may includestoring the first measurement data in the shared memory location andstoring an index to the first measurement data, wherein the index isalso stored in the shared memory location.

[0063] In step 504, a second application may trend, read, or retrievethe first measurement data, or at least a subset of the firstmeasurement data, from the shared memory location on the first computersystem substantially concurrently as the first measurement data islogged to the shared memory location on the first computer system by thefirst application.

[0064] Similar to the first application, the second application mayinclude a plurality of second filter objects which operate to trend thefirst measurement data. The plurality of second filter objects mayinclude a hierarchy of second stream processing objects. The pluralityof first filter objects and the plurality of second filter objects mayshare filter objects.

[0065] Trending may include: (1) generating a query for the firstmeasurement data stored in the shared memory location; (2) determiningthe location of the first measurement data in the shared memory usingthe index of the first measurement data; (3) accessing the firstmeasurement data from the shared memory; and (4) displaying the firstmeasurement data on a display.

[0066] In step 506, the first measurement data stored in the sharedmemory location of the first computer system may be replicated to anarchival database. The replication of the first measurement data may beindependent of the type of measurement data. Thus, the replication maynot require a version of the application software able to read and/orwrite any type of measurement data (i.e., the first application or thesecond application). When updated software to support a new data typefor at least one of the first application and the second application isinstalled on the first computer system, the replication of the firstmeasurement data may support the new data type without modification.

[0067] The archival database may be stored on the first computer system.Alternatively, the archival database may be stored on a second computersystem, the second computer system being coupled to the first computersystem via a network.

[0068] In step 508, the second computer system may transmit thereplicated data to a plurality of computer systems. Similarly, in thecase where the archival database is stored on the first computer system,the first computer system may transmit the replicated data to aplurality of computer systems.

[0069] Although the system and method of the present invention have beendescribed in connection with several embodiments, the invention is notintended to be limited to the specific forms set forth herein, but onthe contrary, it is intended to cover such alternatives, modifications,and equivalents, as can be reasonably included within the spirit andscope of the invention as defined by the appended claims.

What is claimed is:
 1. A method of performing logging and trending ofmeasurement data on a first computer system, the method comprising: afirst application logging first measurement data to a shared memorylocation on the first computer system; a second application trending thefirst measurement data from the shared memory location on the firstcomputer system substantially concurrently as the first measurement datais logged to the shared memory location on the first computer system;wherein the first measurement data comprises one or more types ofmeasurement data; replicating the first measurement data stored in theshared memory location of the first computer system to an archivaldatabase; wherein the replication of the first measurement data isindependent of the type of measurement data.
 2. The method of claim 1,wherein the first application and the second application each supportone or more data types; the method further comprising: installingupdated software for at least one of the first application and thesecond application on the first computer system, wherein the updatedsoftware supports a new data type; wherein the replication of the firstmeasurement data supports the new data type without modification.
 3. Themethod of claim 1, wherein the first application comprises a pluralityof first filter objects which operate to log the first measurement data;wherein the plurality of first filter objects comprise a hierarchy offirst stream processing objects; wherein the second applicationcomprises a plurality of second filter objects which operate to trendthe first measurement data; wherein the plurality of second filterobjects comprise a hierarchy of second stream processing objects.
 4. Themethod of claim 3, wherein the plurality of first filter objects and theplurality of second filter objects share filter objects.
 5. The methodof claim 1, wherein the archival database is stored on the firstcomputer system.
 6. The method of claim 1, wherein the archival databaseis stored on a second computer system; wherein said second computersystem is coupled to said first computer system via a network.
 7. Themethod of claim 6, further comprising: said second computer systemtransmitting the replicated data to a third computer system.
 8. Themethod of claim 6, further comprising: said second computer systemtransmitting the replicated data to a plurality of computer systems. 9.The method of claim 1, wherein said logging comprises: receiving thefirst measurement data from a first measurement device; storing thefirst measurement data in the shared memory location, wherein the sharedmemory location is comprised in a volatile memory, wherein said storingcomprises storing the first measurement data in the shared memorylocation and storing an index to the first measurement data, whereinsaid index is stored in the shared memory location.
 10. The method ofclaim 1, wherein said trending comprises: generating a query for thefirst measurement data comprised in the shared memory location;determining the location of the first measurement data in the sharedmemory using the index of the first measurement data; accessing thefirst measurement data from the shared memory; and displaying the firstmeasurement data on a display.
 11. The method of claim 1, wherein theone or more types of measurement data comprises live data acquired froma data acquisition device.
 12. The method of claim 1, wherein the one ormore types of measurement data comprise one or more of: waveform data;single-point data, wherein single-point data comprises a data value anda data timestamp; alarm data; event data.
 13. A method of storing andretrieving measurement data, the method comprising: a first applicationprogram receiving measurement data of a plurality of data types from aplurality of measurement devices; the first application program storingthe measurement data received from the plurality of measurement devicesin a shared memory location, wherein said storing is independent of thedata type; a second application program retrieving at least a subset ofthe stored measurement data from the shared memory locationsubstantially concurrently with the measurement data being stored in theshared memory location by the first application program; replicating thestored measurement data from the shared memory location to an archivaldatabase; wherein the replication of the stored measurement data isindependent of the data type.
 14. The method of claim 13, wherein thefirst application and the second application each support one or moredata types; the method further comprising: installing updated softwarefor at least one of the first application and the second application onthe first computer system, wherein the updated software supports a newdata type; wherein the replication of the first measurement datasupports the new data type without modification.
 15. The method of claim13, wherein the first application comprises a plurality of first filterobjects which operate to log the first measurement data; wherein theplurality of first filter objects comprise a hierarchy of first streamprocessing objects; wherein the second application comprises a pluralityof second filter objects which operate to trend the first measurementdata; wherein the plurality of second filter objects comprise ahierarchy of second stream processing objects.
 16. The method of claim15, wherein the plurality of first filter objects and the plurality ofsecond filter objects share filter objects.
 17. The method of claim 13,wherein said storing measurement data received from the plurality ofmeasurement devices in a shared memory location further comprises:storing the measurement data in the shared memory location; storing anindex to the measurement data, wherein said index is stored in theshared memory location.
 18. The method of claim 13, wherein theplurality of data types comprises one or more of the following: livedata acquired from a data acquisition device, waveform data,single-point data, alarm data, event data.
 19. A method of performinglogging and trending of measurement data, the method comprising: a firstapplication logging first measurement data to a shared memory location;wherein the first measurement data comprises one or more types ofmeasurement data; wherein the first application comprises a plurality offirst filter objects which operate to log the first measurement data;wherein the plurality of first filter objects comprise a hierarchy offirst stream processing objects; a second application trending the firstmeasurement data from the shared memory location substantiallyconcurrently as the first measurement data is logged to the sharedmemory location; wherein the second application comprises a plurality ofsecond filter objects which operate to trend the first measurement data;wherein the plurality of second filter objects comprise a hierarchy ofsecond stream processing objects.